Phylogenetic revision of the North American Asidini (Coleoptera: Tenebrionidae)

The asidine darkling beetles (Coleoptera: Tenebrionidae: Asidini) are a morphologically diverse tribe of flightless tenebrionids found in many arid and sub‐arid habitats around the world. The 260 currently described North American species are contained in 27 genera, all of which are restricted to the western half of the continent. Evolutionary relationships within and between the North American Asidini (Coleoptera: Tenebrionidae) genera were reconstructed using partial sequences of mitochondrial cytochrome c oxidase I (COI) (660 bp) and nuclear ribosomal 28S (D2 region) (492 bp), and 100 phenotypic characters for 50 North American asidine species, representing 20 of the 27 currently described genera and 1 new genus. Species from two additional tenebrionid tribes (Branchini and Coniontini) and the South American asidine genus Cardigenius were chosen as outgroups. Analyses were performed using maximum parsimony and Bayesian inference methods. Clade support was inferred based on the posterior probability distribution of tree topologies, nonparametric bootstrap analysis, and partitioned Bremer support indices. The generic classification of the North American Asidini is revised based on the results, with ten genera recognized. Seven current genera: Craniotus LeConte, Heterasida Casey, Litasida Casey, Microschatia Solier, Pelecyphorus Solier, Philolithus Lacordaire, Stenomorpha Solier, are redescribed, and Ardamimicus Smith gen.n ., Ferveoventer Smith gen.n . and Micrasida Smith gen.n . are described, including Ardamimicus cognatoi Smith sp.n ., Ferveoventer browni Smith sp.n . and Micrasida obrienorum Smith sp.n . Twenty current genera are treated as subgenera pending further analyses: Philolithus Lacordaire with subgenera Glyptasida Casey, Gonasida Casey, Herthasida Wilke and Tisamenes Champion; Pelecyphorus Solier, with subgenera: Astrotus LeConte, Parasida Casey (= Plesiasida nom.n ), Poliorcetes Champion, Sicharbas Champion, Stenosides Solier, Ucalegon Champion and Zaleucus Champion, and Stenomorpha Solier with subgenera Asidina Casey, Asidopsis Casey, Bothrasida Casey, Megasida Casey, Notiasida Casey, Platasida Casey, Pycnomorpha Motschulsky, Stethasida Casey and Trichiasida Casey; all stat.rev .     

Testing the adaptive hypothesis of Batesian mimicry among hybridizing North American admiral butterflies

Batesian mimicry is characterized by phenotypic convergence between an unpalatable model and a palatable mimic. However, because convergent evolution may arise via alternative evolutionary mechanisms, putative examples of Batesian mimicry must be rigorously tested. Here, we used artificial butterfly facsimiles (N = 4000) to test the prediction that (1) palatable Limenitis lorquini butterflies should experience reduced predation when in sympatry with their putative model, Adelpha californica, (2) protection from predation on L. lorquini should erode outside of the geographical range of the model, and (3) mimetic color pattern traits are more variable in allopatry, consistent with relaxed selection for mimicry. We find support for these predictions, implying that this convergence is the result of selection for Batesian mimicry. Additionally, we conducted mark–recapture studies to examine the effect of mimicry and found that mimics survive significantly longer at sites where the model is abundant. Finally, in contrast to theoretical predictions, we found evidence that the Batesian model (A. californica) is protected from predation outside of its geographic range. We discuss these results considering the ongoing hybridization between L. lorquini and its sister species, L. weidemeyerii, and growing evidence that selection for mimicry predictably leads to a reduction in gene flow between nascent species.     

Historical biogeography of Eusattus muricatus (Coleoptera: Tenebrionidae) within the Great Basin, western North America

Genetics of Eusattus muricatus LeConte (Coleoptera: Tenebrionidae) populations within the Lahontan Basin and the Lahontan Trough of the Great Basin, western North America were assayed using protein electrophoresis. Two similar population phenograms were developed using neighbour-joining and maximum likelihood algorithms. An area cladogram was developed using geological data. Maximum likelihood phenogram and area cladogram were compared to test for congruence between geology and phylogeny. Pairwise regressions of estimated gene flow measures ( Nm ) yielded a significant relationship for populations within the Lahontan Basin but not for the Lahontan Trough. Protein molecular clock calculations showed that populations within the Lahontan Basin were primarily differentiating according to the dune/subbasin isolation events predicted by the area cladogram.     

Learning of salient prey traits explains Batesian mimicry evolution

Batesian mimicry evolution involves an initial major mutation that produces a rough resemblance to the model, followed by smaller improving changes. To examine the learning psychology of this process, we applied established ideas about mimicry in Papilio polyxenes asterius of the model Battus philenor. We performed experiments with wild birds as predators and butterfly wings as semiartificial prey. Wings of hybrids of P. p. asterius and Papilio machaon were used to approximate the first mutant, with melanism as the hypothesized first mimetic trait. Based on previous results about learning psychology and imperfect mimicry, we predicted that: melanism should have high salience (i.e., being noticeable and prominent), meaning that predators readily discriminate a melanistic mutant from appearances similar to P. machaon; the difference between the first mutant and the model should have intermediate salience to allow further improvement of mimicry; and the final difference in appearance between P. p. asterius and B. philenor should have very low salience, causing improvement to level off. Our results supported both the traditional hypothesis and all our predictions about relative salience. We conclude that there is good agreement between long‐held ideas about how Batesian mimicry evolves and recent insights from learning psychology about the role of salience in mimicry evolution.     

Wing pattern evolution and the origins of mimicry among North American admiral butterflies (Nymphalidae: Limenitis)

The evolution of wing pattern diversity in butterflies has emerged as a model system for understanding the origins and maintenance of adaptive phenotypic novelty. Admiral butterflies (genus Limenitis) are an attractive system for studying wing pattern diversity because mimicry is common among the North American species and hybrid zones occur wherever mimetic and non-mimetic wing pattern races meet. However, the utility of this system has been limited because the evolutionary relationships among these butterflies remain unclear. Here I present a robust species-level phylogeny of Limenitis based on 1911 bp of two mitochondrial genes (COI and COII) and 904 bp of EF1-alpha for all five of the Nearctic species/wing pattern races, the majority of the Palearctic species, and three outgroup genera; Athyma, Moduza (Limenitidini), and Neptis (Limenitidinae: Neptini). Maximum-likelihood and Bayesian analyses indicate that the North American species are a well-supported, monophyletic lineage that is most closely related to the widespread, Palearctic, Poplar admiral (L. populi). Within North America, the Viceroy (L. archippus) is the basal lineage while the relationships among the remaining species are not well resolved. A combined maximum-likelihood analysis, however, indicates that the two western North America species (L. lorquini and L. weidemeyerii) are sister taxa and closely related to the wing pattern subspecies of the polytypic Limenitis arthemis species complex. These results are consistent with (1) an ancestral host-shift to Salicaceae by the common ancestor of the Poplar admiral and the Nearctic admiral lineage, (2) a single colonization of the Nearctic, and (3) a subsequent radiation of the North American forms leading to at least three independent origins of mimicry.     

Phylogeny of North American fireflies (Coleoptera: Lampyridae): implications for the evolution of light signals

Representatives of the beetle family Lampyridae ("fireflies", "lightningbugs") are well known for their use of light signals for species recognition during mate search. However, not all species in this family use light for mate attraction, but use chemical signals instead. The lampyrids have a worldwide distribution with more than 2000 described species, but very little is known about their phylogenetic relationships. Within North America, some lampyrids use pheromones as the major mating signal whereas others use visual signals such as extended glows or short light flashes. Here, we use a phylogenetic approach to illuminate the relationships of North American lampyrids and the evolution of their mating signals. Specifically, to establish the first phylogeny of all North American lampyrid genera, we sequenced nuclear (18S) and mitochondrial (16S and COI) genes to investigate the phylogenetic relationships of 26 species from 16 North American (NA) genera and one species from the genus Pterotus that was removed recently from the Lampyridae. To test the monophyly of the NA firefly fauna we sequenced the same genes from three European lampyrids and three Asian lampyrids, and included all available Genbank data (27 additional Asian lampyrids and a former lampyrid from Asia, Rhagophthalmus). Our results show that the North American lampyrids are not monophyletic. Different subgroups are closely related to species from Europe, Asia and tropical America, respectively. The present classification of fireflies into subfamilies and tribes is not, for the most part, supported by our phylogenetic analysis. Two former lampyrid genera, Pterotus and Rhagophthalmus, which have recently been removed from this family, are in fact nested within the Lampyridae. Further, we found that the use of light as a sexual signal may have originated one or four times among lampyrids, followed by nine or four losses, respectively. Short flashes originated at least twice and possibly three times independently among our study taxa. The use of short flashes as a mating signal was replaced at least once by the use of long glows, and light signals as mating signals were lost at least three times in our study group and replaced by pheromones as the main signal mode.     

High-model abundance may permit the gradual evolution of Batesian mimicry: an experimental test

In Batesian mimicry, a harmless species (the ‘mimic’) resembles a dangerous species (the ‘model’) and is thus protected from predators. It is often assumed that the mimetic phenotype evolves from a cryptic phenotype, but it is unclear how a population can transition through intermediate phenotypes; such intermediates may receive neither the benefits of crypsis nor mimicry. Here, we ask if selection against intermediates weakens with increasing model abundance. We also ask if mimicry has evolved from cryptic phenotypes in a mimetic clade. We first present an ancestral character-state reconstruction showing that mimicry of a coral snake (Micrurus fulvius) by the scarlet kingsnake (Lampropeltis elapsoides) evolved from a cryptic phenotype. We then evaluate predation rates on intermediate phenotypes relative to cryptic and mimetic phenotypes under conditions of both high- and low-model abundances. Our results indicate that where coral snakes are rare, intermediate phenotypes are attacked more often than cryptic and mimetic phenotypes, indicating the presence of an adaptive valley. However, where coral snakes are abundant, intermediate phenotypes are not attacked more frequently, resulting in an adaptive landscape without a valley. Thus, high-model abundance may facilitate the evolution of Batesian mimicry.     

The occurrence of synchrony in the North American fireflyPhotinus carolinus (Coleoptera: Lampyridae)

Synchronous flashing has been described for some Southeast Asian fireflies but has rarely been reported in North American fireflies. Our field observations indicated thatPhotinus carolinus flash synchronously. The flash pattern of individualP. carolinus was characterized by a burst of five to eight flashes over a period of approximately 4 s. These flash bursts were repeated about every 12 s. Groups of fireflies comprised individuals exhibiting this species-specific flash pattern. Remarkably, members of the group flashed synchronously: Flash bursts started and stopped at the same time and the flashes among individuals occurred at the same time as well. We used low-light level videography to examine this behavior in caged groups of (3 or 10) fireflies for synchronic flashing. The occurrence of concurrent rhythmic group flashing satisfies the criteria for synchrony as defined by Buck (1988). The intermittent nature of the bursts of flashes shown byP. carolinus makes this a discontinuous synchrony. The mechanisms underlying discontinuous synchrony are not known.     

Karyological differences among Tenebrionidae (Coleoptera)

Karyotypes obtained from spermatogonial metaphases of 20 tenebrionid species have been surveyed. The range of chromosome numbers is from 2n=16 to 2n=26, but only five species deviate from 2n=20, which is the modal and most primitive number of the family. Only the tribe Akidini shows a clear relationship between chromosome number (2n=16) and taxonomic group, while in the other species this relationship is not apparent. The mean total complement lengths in eleven species vary about twofold and the number of chromosome arms (NF) from 23 to 50. Some congeneric species ofTentyria, Hegeter andErodius displayed slight differences in the number of acrocentric chromosomes.Project number PB 87-0584-C02-01, Ministry of Education and Science, Spain     

Mechanisms of synchrony in the North American fireflyPhotinus carolinus (Coleoptera: Lampyridae)

Photometric recordings combined with computer stimulation, acquisition and analysis were used to study synchrony in the North American fireflyPhotinus carolinus. A computer-generated burst of simulatedP. carolinus flashes was used to trigger a firefly flash burst. We found that the first triggered firefly flashes occurred after the second or third flashes in the stimulus burst, that there were fewer flashes in a triggered burst than a spontaneous burst, and that extending the stimulus flashes into the firefly's interburst interval inhibited firefly flashing. When the stimulus flash interval (389–560 ms) was changed, no change was seen in the interflash interval. When the stimulus flash interval was changed, the average time between stimulus flash and firefly flash (flash delay) changed as if the firefly interflash interval was constant. Thus, interflash interval inP. carolinus does not change its length, making it similar to the Southeast Asian synchronizerPteroptyx cribellata and different fromPteroptyx malaccae, which can change its interval. We suspect that the time between bursts is functionally analogous to the time between flashes in Southeast Asian synchronizers.     

Dynamics of the evolution of Batesian mimicry: molecular phylogenetic analysis of ant-mimicking Myrmarachne (Araneae: Salticidae) species and their ant models

Batesian mimicry is seen as an example of evolution by natural selection, with predation as the main driving force. The mimic is under selective pressure to resemble its model, whereas it is disadvantageous for the model to be associated with the palatable mimic. In consequence one might expect there to be an evolutionary arms race, similar to the one involving host-parasite coevolution. In this study, the evolutionary dynamics of a Batesian mimicry system of model ants and ant-mimicking salticids is investigated by comparing the phylogenies of the two groups. Although Batesian mimics are expected to coevolve with their models, we found the phylogenetic patterns of the models and the mimics to be indicative of adaptive radiation by the mimic rather than co-speciation between the mimic and the model. This shows that there is strong selection pressure on Myrmarachne, leading to a high degree of polymorphism. There is also evidence of sympatric speciation in Myrmarachne, the reproductive isolation possibly driven by female mate choice in polymorphic species.     

中华漠王Platyope proctoleuca chinensis(鞘翅目:拟步甲科)对微生境的选择

动物对栖息地选择是复杂的,探索其内在机制对寻求维持动物多样性的有效方法具有重要意义。以古尔班通古特沙漠的地表甲虫优势种——中华漠王(Platyope proctoleuca chinensis)(鞘翅目:拟步甲科)为研究对象,2007—2008年连续2年采用陷阱捕获法监测其在不同生境下的种群数量和洞穴数量,分析该甲虫在景观和微尺度环境下对栖息地的选择。结果表明:在景观尺度上,与垄间相比,中华漠王更喜欢在沙丘上活动,在沙丘不同坡面上,中华漠王在背风坡的种群数量大于迎风坡;在微尺度上,中华漠王喜好沙丘上部的微环境,在背风坡上部种群数量相对更多;洞穴数量在景观和微生境2种尺度上的分布基本与种群数量空间分布一致。此外,中华漠王对微生境的选择与洞穴建立的难易程度有关,而洞穴的建立与土壤质量密切相关,特别是土壤的物质组成及其硬度。     

A revised subfamily classification of Tenebrionidae (Coleoptera)

Existing classifications of Tenebrionidae are reviewed briefly. The inclusion of the families Alleculidae, Lagriidae, and Nilionidae in Tenebrionidae is confirmed. The splitting off from this complex of a family, Tentyriidae, by Doyen is discussed and rejected. Various taxa which had been included in Tenebrionidae are excluded, amongst which Syrphetodes, Brouniphylax, Exohadrus, Arthopus, Cotulades, Docalis, and Latometus (=Elascus) have not previously been formally excluded. A new family, Archeocrypticidae, is established and defined briefly for Archeocrypticus, Sivacrypticus, and Enneboeus.

Data from matrices based on adult and larval characters comparing Tenebrionidae with most other families of Tenebrionoidea (=Heteromera) are presented for derived characters in common, and for overall similarity. The families most closely related to Tenebrionidae according to these data are Zopheridae, Chalcodryidae, Merycidae, Archeocrypticidae, Synchroidae, Colydiidae, and Monommatidae; none is very close to Tenebrionidae, which has had a long independent history.

Characters of the subfamilies recognised are tabulated, and interpreted in a phylo‐genetic dendrogram. Phylogeny is discussed in relation to adaptive changes in the biology of the various subfamilies, which are Zolodininae new subfamily, Pimeliinae new sense (including Tentyriinae), Toxicinae new sense, Phrenapatinae new sense (including Archeoglenini new tribe), Diaperinae new sense, Gnathidiinae, Tenebrioninae new sense, Alleculinae, Nilioninae, Lagriinae new sense, Cossyphinae, and Cossyphodinae new status.

Biology, economic importance, copulation, orientation of the aedeagus, and distribution are discussed briefly.

Definitions of the family and subfamilies and a key to subfamilies are given, and keys to tribes are included for the smaller subfamilies. The previously unknown larvae of the genera Zolodinus, Menimus, Archeoglenes, Lepispilus, and Nyctoporis are described in detail. Pupae of Zolodinus and Nyctoporis are described. Keys to larvae include many other genera which were hitherto unknown or poorly known.     

Molecular insights into the phylogeny of Blapstinina (Coleoptera: Tenebrionidae: Opatrini)

The monophyly of the North and South American endemic subtribe Blapstinina (Tenebrionidae: Opatrini) is tested through phylogenetic analyses using five molecular markers [nuclear ribosomal 28S (28S), cytochrome oxidase subunit II (COII), arginine kinase (ArgK), carbamoyl-phosphate synthetase domain of rudimentary (CAD), wingless (wg)]. Representatives of several opatrinoid subtribes were taken into consideration, including other geographically overlapping endemic genera, namely Ammodonus, Ephalus and Pseudephalus (all previously considered representatives of Ammobiina). A comparative study of morphology was performed to assess resulting phylogenetic hypotheses. Analyses support the monophyly of Blapstinina; however, they also strongly indicate that Ammodonus should be included within the subtribe. Mecysmus is nested within Blapstinus and therefore, a new synonymy, Blapstinus (= Mecysmus syn.n. ), and the following combinations are introduced: Blapstinus advena comb.n. , B. angustus comb.r. , B. laticollis comb.n. , B. parvulus comb.n. , B. tenuis comb.n. Morphological analysis showed a close affiliation between Ephalus and Pseudephalus. Based on these results, Pseudephalus is synonymized with Ephalus [Ephalus (= Pseudephalus syn.n. )], and the following combination is introduced: Ephalus brevicornis comb.n. Recovered topologies also strongly support transferring Ephalus stat.n. into Opatrina, making the distribution of Opatrina amphi-Atlantic.     

The environmental basis of North American species richness patterns among Epicauta (Coleoptera: Meloidae)

Understanding regional variability in species richness is necessary for conservation efforts to succeed in the face of large-scale environmental deterioration. Several analyses of North American vertebrates have shown that climatic energy provides the best explanation of contemporary species richness patterns. The paucity of analyses of insect diversity patterns, however, remains a serious obstacle to a general hypothesis of spatial variation in diversity. We collected species distribution data on a North American beetle genus, Epicauta (Coleoptera: Meloidae) and tested several major diversity hypotheses. These beetles are generally grasshopper egg predators as larvae, and angiosperm herbivores as adults. Epicauta richness is highest in the hot, dry American southwest, and decreases north and east, consistent with the species richness-energy hypothesis. Potential evapotranspiration, which is also the best predictor of richness patterns among North American vertebrates, explains 80.2% of the variability in Epicauta species richness. Net primary productivity and variables measuring climatic heat energy only (such as PET) are not generally comparable, though they are sometimes treated as if they were equivalent. We conclude that the species richness-energy hypothesis currently provides a better overall explanation for Epicauta species richness patterns in North America than other major diversity hypotheses. The observed relationship between climatic energy and regional species richness may provide significant insight into the response of ecological communities to climate change.     

Thermal death kinetics of red flour beetle (Coleoptera: Tenebrionidae)

While developing radio frequency heat treatments for dried fruits and nuts, we used a heating block system developed by Washington State University to identify the most heat-tolerant life stage of red flour beetle, Tribolium castaneum (Herbst), and to determine its thermal death kinetics. Using a heating rate of 15 degrees C/min to approximate the rapid heating of radio frequency treatments, the relative heat tolerance of red flour beetle stages was found to be older larvae > pupae and adults > eggs and younger larvae. Lethal exposure times for temperatures of 48, 50, and 52 degrees C for the most heat-tolerant larval stage were estimated using a 0.5th order kinetic model. Exposures needed for 95% mortality at 48 degrees C were too long to be practical (67 min), but increasing treatment temperatures to 50 and 52 degrees C resulted in more useful exposure times of 8 and 1.3 min, respectively. Red flour beetle was more sensitive to changes in treatment temperature than previously studied moth species, resulting in red flour beetle being the most heat-tolerant species at 48 degrees C, but navel orangeworm, Amyelois transitella (Walker), being most heat tolerant at 50 and 52 degrees C. Consequently, efficacious treatments for navel orangeworm at 50-52 degrees C also would control red flour beetle.